1. Field of the Invention
The present invention pertains to a drive system, especially for a motor vehicle, having a centrifugal mass mounted on a drive shaft and an electrical machine with a rotor mounted on the centrifugal mass and a stator arranged radially with respect to the rotor.
2. Description of the Related Art
Drive systems of this type can be designed in many different ways and usually have, first, a prime mover. A prime mover of the type in question can be, for example, a combustion machine such as an internal combustion engine or the like. Drive systems of the known type also usually have a drive unit, which can be built up in turn out of various components. For example, the drive unit can have a drive shaft, by means of which the torque produced by the prime mover can be transmitted to other components. The drive unit can also include a centrifugal mass arrangement, which is mounted on the drive shaft. The drive unit can also have an electrical machine.
In general, these electrical machines can be rotating machines, for example, which use a magnetic field to convert electrical energy into mechanical energy according to the motor principle or mechanical energy into electrical energy according to the generator principle.
These types of electrical machines, which can be designed either as synchronous machines or as asynchronous machines, usually have a first machine component and a second machine component. The two machine components rotate relative to each other or can be rotated relative to each other. The two machine components are mounted adjacent to each other in the radial direction. One of the two machine components is usually mounted radially inside the other machine component with respect to the axis of rotation of the electrical machine. Depending on the design of the electrical machine, one of the machine components can be a rotor arrangement and the other machine component can be a stator arrangement. The stator arrangement, also called simply the stator, is usually the stationary part, whereas the rotor arrangement, also called simply the rotor, is the rotating part.
Depending on the design of the electrical machine, the stator component consists, for example, of a sheet packet, which forms a yoke and a number of teeth. The electrical windings are laid in the grooves between the teeth. The magnetic field of the electrical machine is produced when current passes through these windings. The rotor arrangement consists, for example, of a sheet packet, on which a number of magnets, possibly permanent magnets, are mounted.
One of the areas in which electrical machines are used is that of vehicles of all types. In vehicles, electrical machines are used in their function as generators. When these electrical machines thus operate according to the generator principle, they produce electrical energy, which can then be made available to other consumers. In another application in vehicles, electrical machines are used as starter-generators, for example. A starter-generator is an electrical machine which is mounted between the drive shaft of a prime mover, such as the crankshaft of an internal combustion engine, and a component of the drive unit, possibly a clutch, a gearbox, or the like, in the drive system of the vehicle. The starter-generator can be used, first, to start the prime mover. Once the vehicle is in operation, it can also operate as a generator and can therefore replace both the starter and the generator in the vehicle.
In addition to the components already described above, the drive unit can also include other components, which can include, for example, a clutch, a gearbox, a torque converter, etc.
A drive system of this type is described in, for example, DE 199 27 261. These types of drive systems are used to advantage in motor vehicles. Especially in the vehicle sector, however, the need to reduce the amount of space required for the drive system is increasing. This can be explained by advances in engineering, which make it necessary to accommodate ever-increasing numbers of components in the engine compartment of the vehicle. The solution disclosed in the publication cited above already offers a way to reduce the space required to accommodate the drive system.